Active electronically steered antenna systems (“AESA systems,” a type of “phased array system”) form electronically steerable beams for a wide variety of radar and communications systems. To that end, AESA systems typically have a plurality of beam forming elements (e.g., antennas) that transmit and/or receive energy so that the signal on each beam forming element can be coherently (i.e., in-phase and amplitude) combined (referred to herein as “beam forming” or “beam steering”). Specifically, many AESA systems implement beam steering by providing a unique RF phase shift and gain setting (phase and gain together constitute a complex beam weight) between each beam forming element and a beamforming or summation point.
The number and type of beam forming elements in the phased array system can be selected or otherwise configured specifically for a given application. A given application may have a specified minimum equivalent/effective isotropically radiated power (“EIRP”) for transmitting signals. Additionally, or alternatively, a given application may have a specified minimum G/T (analogous to a signal-to-noise ratio) for receiving signals, where:                G denotes the gain or directivity of an antenna, and        T denotes the total noise temperature of the receive system including receiver noise figure, sky temperature, and feed loss between the antenna and input low noise amplifier.        